The present invention relates to a pouring device for a canister-shaped container having a pouring spout which can be sealed by a sealing cap and which receives a retaining ring for an aeration pipe running at least approximately parallel to the retaining ring, which is set thereon in the upper peripheral section of the retaining ring relative to the pouring position.
If the fluid stream flowing out of the pouring opening of an otherwise closed container blocks the air intake an increasing subpressure builds up in the container on account of the decreasing volume of fluid, which, on reaching a certain magnitude, results in air breaking through the pouring opening and thus equalises the pressure, with the result that a subpressure again builds up in the container and the procedure is repeated. The pressure fluctuations in the container give rise to an irregular gushing pouring stream in cooperation with the air bubbles sucked in through the pouring opening, which not only has a disadvantageous effect on the emptying rate, but also makes it difficult to accurately direct the pouring stream relative to a filling aperture, for example. For steadying the pouring stream various pouring devices have already been put forward, common to which is the fact that an aeration pipe running parallel to the axis of the pouring spout is provided, which is set in the pouring spout of the container by means of a retaining ring such that it is located in the upper peripheral section of the pouring spout in the pouring position so that air can enter the container through this aeration pipe and effect pressure equalisation. But since the preferably short aeration pipe is in the vicinity of the fluid stream and is impacted thereby, any steadying of the pouring stream attained with such a pouring device remains unsatisfactory in canister-shaped containers in particular.
In order to avoid a suction effect of the pouring stream hindering air intake into the container it has already been proposed (DE 297 20 426 U1) to insert a pipe socket running at an oblique angle into the pouring spout of the container, which presents at least one intake aperture in the upper peripheral section relative to the pouring position, which is shielded by a front wall of the pipe socket relative to the fluid flow. This wall separates an air pocket out from the fluid stream by the pipe socket in the vicinity of the through opening, which facilitates air entry into the container through the through opening in the pipe socket. Despite this measure the resulting pouring stream may be uneven if the air intake to the air pocket is hindered by the pouring flow. Similar difficulties can also occur with another known pouring device (DE 196 15 906 A1), wherein an aeration pipe running transversely to the axis of the pouring spout is arranged at an axial distance to the pouring spout on a retaining ring set in the pouring spout and exhibits a protective wall in the vicinity of the air intake opening relative to the fluid flow, because again the air intake to the air pocket formed by the protective wall can be impaired by the pouring stream.
The object of the invention therefore is to develop a pouring device for canister-shaped containers of the type initially outlines such that the container can be continuously emptied with an even flow.
The invention solves this task by the fact that the aeration pipe is closed at its end averted from the retaining ring and in the vicinity of its upper peripheral section in the pouring position exhibits at least one through opening terminating in the container having a smaller through cross-section than the internal pipe cross-section.
Since the aeration pipe set on the retaining ring extends in the vicinity of the pouring spout the air intake into this aeration pipe cannot be hindered for an extended period by the pouring stream leaving the pouring spout; at the same time this aeration pipe is closed at its end averted from the retaining ring and therefore cannot be impacted by the fluid flow. Aeration of the container required for pressure equalisation can thus be effected advantageously via the through opening of the aeration pipe, which is provided on the side averted from the pouring stream in an upper peripheral section of the aeration pipe relative to the pouring position. Since the internal pipe cross-section is greater than the through cross-section of the through opening, there is always an adequate air supply inside the aeration pipe for even metered aeration of the container to be guaranteed via the through opening in the sleeve of the aeration pipe.
Particularly advantageous aeration ratios result when on the outer periphery of the aeration pipe on the side of the through opening facing the retaining ring a deflecting baffle is provided thereon partially enclosing the former, which supports even passage of air through the through opening into the container. This deflecting baffle needs to project only slightly over the outer periphery of the aeration pipe to be able to have a corresponding influence on the air guidance. For this reason axial introduction of the aeration pipe into the pouring spout of the container is not hindered by this deflecting baffle, in particular if the deflecting baffle falls away towards the close end of the aeration pipe. In addition, the aeration pipe can be inclined slightly inwards towards the axis of the retaining ring to enable coaxial introduction of the retaining ring with the aeration pipe into the pouring spout of the container in spite of the deflecting baffle projecting outwards from the aeration pipe.
The pouring procedure can also be improved by the fact that at least one more through opening having a smaller through cross-section is provided between the through opening arranged in the vicinity of the sealed end of the aeration pipe and the pouring spout of the container. This additional through opening allows finer air bubbles to enter the container, thus supporting the desired even pressure equalisation.
Because the aeration pipe has to be provided on the upper peripheral side of the pouring spout determined by the pouring position, a corresponding built-in position of the retaining ring is to be provided in the pouring spout of the container. For this purpose a rotating safety device formed by limit stops, which provides the proper rotary position of the retaining ring in the pouring spout of the container when the pouring device is being mounted, can be formed between the retaining ring and the pouring spout of the container, if the retaining ring is introduced to the pouring spout using a rotary motion, for example. Such mounting of the pouring device can be undertaken in particularly simple fashion if the sealing cap forms an assembly unit with the retaining ring bearing the aeration pipe able to be inserted positively into the sealing cap. In this case only the aeration pipe is to be guided over the sealing cap into the pouring spout such that the sealing cap can be set on the pouring spout. When the pouring spout of the container is sealed by the sealing cap the retaining ring is pressed as a seal into the pouring spout, whereby the rotary displacement of the retaining ring as far as the limit stop of the rotating safety device forces the proper fitting position of the pouring spout when screw caps are used. When the sealing cap is removed the retaining ring remains in the pouring spout of the container as a result of its press fit.